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points to Hei conversion/ CARB ???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by NoSmog73, May 20, 2002.

  1. NoSmog73

    NoSmog73 1/2 ton status

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    Ok I got saved by the AAA truck this morning....I was smelling raw gas and could see it coming out the tailpipe and when I tried to start it It wouldn't fire but if I held the pedal to the floor it would want to start but not....
    So I was thinking what could be wrong....
    When I started it to leave it would start in the driveway but ran very rough like a very very extreme cam...
    Then with me giving it gas it would idle it self out of the rough idle and idle smooth.../forums/images/icons/mad.gif
    Then at the gas station it wouldn't start (see above).... So could it be a combo of an adjustment on the carb and not enough spark (i.e warn points = change to hei )

    I have a q-jet (points)msd-offroad,edlebrock intake
    Thanks Mike
     
  2. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    It's either points or the choke is stuck on.
    Scrap the points. a HEI is a drop in. Makes a world of difference. you can either hit the local parts store and just buy the parts or get one from the junk yard.
    What you will need it the housing, cap, rotor and ground strap. Also need to get the plugs for HEI. Ask for plugs for say a 79. I think you will also need wires. I converted my 70 Ponitac and it was right at $200 from the local parts place. Will probably be less since the Pontiac Distributor housing in more expensive.
     
  3. NoSmog73

    NoSmog73 1/2 ton status

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    Thanks grim any idea how to tell if the choke is "stuck" It is a dumb ?? but I am very carb dumb....mike
    P.S. any word on the tops....
     
  4. 70~K5

    70~K5 1/2 ton status

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    Take the aircleaner lid off and look at the front barrels of the carb. When the plate closes the opening the choke is on. When the plate is up and down the choke is off. Mine sticks and after it warms up I have to pop the little rod that leads to it to get the choke to open.
     
  5. NoSmog73

    NoSmog73 1/2 ton status

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    So what's a good way to get the flap to stay open when it should be open rather than to keep popping the cleaner and tapping it....mike thanks
     
  6. TopOff

    TopOff 1/2 ton status

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    Check fuel-pressure and fuel float too. If either are too high, you will be running rich.

    I had a rochester that couldn't stop the fuel from coming on on the floats because of the new fuel-pump was putting out ~10 psi. I would think a fuel-pressure regulator will help.

    Good luck.
     
  7. 70~K5

    70~K5 1/2 ton status

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    I don't have to take the aircleaner off as I have one of those tall adpters between the carb and airclear that came stock on the first gens. All I do is once it's warmed up open the hood and push up on the choke rod where it runs up to the plate. Someday I'll fix it right but for now if some one where to steal my blazer they wouldn't get to far till it acted up.
     
  8. NoSmog73

    NoSmog73 1/2 ton status

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    Ok I just started it and I sould see the flap with a little gap but not all the way closed and when I opened the flap with my hand the rpm's picked up where they should have been ''''.....
    So how can I get that flap to open more ..I did turn the fast idle cam screw and got it idling ok so was that the right move....mike
     
  9. NoSmog73

    NoSmog73 1/2 ton status

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  10. 70~K5

    70~K5 1/2 ton status

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    Mine sticks on the cam at the bottom of the rod that runs down from the choke plate.
     
  11. NoSmog73

    NoSmog73 1/2 ton status

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    Ya I can move the rod with my hands but I cant see if there is any kind of adjustment that I could do to it..Oh well...mike
     
  12. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    There is a bimetal spring in a little "Stove" bolted to the top of the intake. The choke flap is controled by it. As the engine heats it causes the spring to change shape and move the rod to open the choke plate. That is proably what's wrong. Spring may have broken with age. It takes about 5-10 minutes (depending oin outside temp) for the choke to fully cycle from cold start. Sounds like it was already warm since the idle picked up when you opened the choke plate. If it was stone cold it should have stumbled.
    Most parts stores should have the Choke stove. Not very expensive. I'll be doing away with mine as soon as I can get the time to rebuild a newer carb that I'm converting to electric choke. Those style chokes are prone to problems.
    You can get rid of yours by doing a manual choke conversion. They sell the cables at Pep Girls if you want to go that route.
     
  13. NoSmog73

    NoSmog73 1/2 ton status

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    I feel dumb I should have said that it was an electeric choke and it is a fairly new jet carb Q-jet...Sorry..mike
     
  14. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Ahhh that a VERY important thing to know /forums/images/icons/smile.gif
    Get a Test light. Check that you have 12v at the Choke power wire with the truck running (if it's wired correctly there will be a oil pressure switch in line to cut power to the choke if the engine is not running). If you got 12v there then 95% chance it's just a bad electric choke element. THey go from time to time.
    Before you pull the old one mark the housing in some way that you will be able to line up the new element the same way. The element may have three rivits holding it in. 1/8 drill bit just till you get the head off. The new element will come with screws to replace the rivits. When you pull the element out do it very slowly and have some light so you can see how it connects to the fork in the housing. Most will have three fingers sticking up and a hook in the end of the bimetal spring on the choke element will wrap around the middle one. What ever one it's on the old one get the new one on the same one.
    Between the choke housing in the carb body is a weight on the high idle cam. lift up on that and the choke should pop open and stay. Give it about half throttle and the choke should close. Fire it up and let it idle. The choke should fully open in a couple minutes. Might need to burp the throttle to get it off high idle.
    That should fix you up.
     
  15. blazer74

    blazer74 Member Premium Member

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    If you go to HEI you will need to replace the power wire to the distributor. The point system uses a resistance wire that does not supply a full 12 volts to the distributor. You can run a heavier wire in place of the original wire to the starter solenoid. I ran mine directly to the ignition side of the fuse panel. Make sure you get the early HEI dist with the four prong module. Never mess with points again.
     

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